In cold weather, low temperatures cause the body to lose heat. But the wind also takes heat from the body, so a temperature reading doesn’t always tell us how cold it really feels.
The wind chill factor was devised by weathermen to show how the temperature and the wind combine to produce the feeling of cold on the human body.
According to the wind chill table, when the temperature is 30 degrees and the wind is blowing at five miles per hour, the temperature feels like 29 degrees. But with the temperature at the same 30 degrees and the wind blowing at 25 miles per hour, it feels the same as it would if the temperature was one degree!
If the temperature is 20 degrees, a five-mile-per-hour wind would make it feel like 19 degrees, but a 25-mile-per-hour wind would make it feel like 25 degrees below zero.